When White House political adviser Karl Rove signaled last week that President Bush planned to veto the stem cell bill being considered by the Senate, the reasons he gave went beyond the president's moral qualms with research on human embryos.

In fact, Rove waded into deeply contentious scientific territory, telling the Denver Post's editorial board that researchers have found "far more promise from adult stem cells than from embryonic stem cells."

The administration's assessment of stem cell science has extra meaning in the wake of the Senate's 63-37 vote Tuesday to expand federal funding of embryonic stem cell research. The measure, which passed the House last year, will now head to Bush, who has vowed to veto it.

But Rove's negative appraisal of embryonic stem cell research - echoed by many opponents of funding for embryonic stem cells - is inaccurate, according to most stem cell scientists, including a dozen contacted for this story.

The field of stem cell medicine is too young and unproven to make such judgments, experts say. Many of those researchers either specialize in adult stem cells or share Bush's moral reservations about embryonic stem cells.

"(Rove's) statement is just not true," said Dr. Michael Clarke, associate director of the stem cell institute at Stanford University, who in 2003 published the first study showing how adult stem cells replenish themselves.

If opponents of embryonic research object on moral grounds, "I'm willing to live with that," Clarke said, though he disagrees. But, he said, "I'm not willing to live with statements that are misleading."

Conservatives who oppose stem cell research on moral grounds are making up scientific claims to prove their point. Further proof that many conservatives will lie and cheat to get their way.